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In this paper, a model for a solid oxide fuel cell (SOFC) system for decentralized electricity production is developed and studied. The proposed system, operated on natural gas, consists of a planar anode supported fuel cell section and a balance of plant (BoP) which includes gases supply, a fuel processor, a heat management system, an after-burner and a power conditioning system. A reference case is defined and evaluated taking into account the state of the art of the technology and the related technical constrains. Electrical and thermal efficiency of the system, for non-reference conditions are evaluated. In particular, the effect of the deviation from the reference conditions of fuel utilization, gas temperature spring in fuel cell stack, anode off-gas recirculation rate, air inlet temperature and external pre-reforming reaction extent is analyzed. The present study revealed to be a powerful tool for evaluating the SOFC system performance under a wide range of operation and paves the way for defining control strategies in order to maintain high system efficiency under part-load operations.

In this paper, a model for a solid oxide fuel cell (SOFC) system for decentralized combined heat and power (CHP) production has been developed and studied. The proposed system, fuelled by natural gas, consists of a SOFC stack of 1 kWe of nominal power and a balance of plant (BoP) which includes gases supply, fuel processing, heat management, start-up equipment, power conditioning and control system. A starting point scenario is calculated based on a simple system flowsheet (external steam generation and no recirculation of exhaust gases) and basic operation parameters. The analysis of the global efficiency of the system is carried out varying the plant concept. The proposed configuration lead to several heat management options which are assessed by energetic balances.

Energy recovery from waste represents an important way to reduce the amount of electric energy to be produced using fossil fuels, i.e. non-renewable sources of energy. Moreover, the energy recovery practice can present interesting economic revenues. Since, at the present time, a large amount of waste is disposed in landfills, it is clear how the use of end life products as fuel can present a noticeable relevance. In the present study, different landfill gas (LFG) energy recovery systems, including traditional and innovative technologies, are analyzed through a technoeconomic and an environmental comparison.

Biogas recovery is an environmentally friendly and cost-effective practice that is getting consensus in both the scientific and industrial community, as the growing number of projects demonstrate. The use of fuel cells as energy conversion systems increases the conversion efficiency, as well as the environmental benefits. Molten carbonate fuel cells (MCFC) operate at a temperature of about 650 °C, thus presenting a high fuel flexibility, compared to low temperature fuel cells. Aim of the present study is to compare the performance of an MCFC single cell, fuelled with different biogas types as well as methane. The biogases considered are derived from the following processes: (1) steam gasification in an entrained flow gasifier; (2) steam gasification in a duel interconnect fluidized bed gasifier; (3) biogas from an anaerobic digestion process. The performances are evaluated for different fuel utilization and current densities. The results are an essential starting point for a complete system design and demonstration.

The aim of the present work is to assess the requirements of an SOFC mathematic model for system simulation. Several models can be found in the literature to predict fuel cells electrochemical and thermo-fluid-dynamic characteristics, but these models are generally based on local characteristics, such as gas concentration, temperature, pressure and so on. The equations representing these characteristics can be in a finite or differential form, but, in any case, they are locally solved using a mesh. The obtainable results can be very useful to guide future researches for FC improvements and optimization. On the other hand, most of these data are useless if the FC system has to be modeled. In this situation, in fact, what is necessary for mathematic modeling are just the discharge characteristics, such as outlet gas composition and temperature, the electric current and power provided. Moreover, calculations for micro-model solution imply numerical methods that are often complex and time consuming. Since during FC systems parametric analyses, the FC characteristics can be computed up 2 hundred times, the need for an easy model is crucial. In applying the local equations as “global”, however, some problems can arise. In the present work, a review of the most significant SOFC models is conducted and then the possibility of their use in a macro-model is evaluated. Different results can be generated according to the assumptions made when adapting micro-model equations to a macro-model. A quantitative analysis of these differences is finally performed and the reliability of the model is estimated.

In Part 1 of the present study it was shown that the equations governing SOFC electrochemical behavior must be locally considered, since a zero-dimensional approximation can lead to inaccurate results. Nevertheless, it was also emphasized that a SOFC model must be as simple as possible, when the whole system is simulated and parametric analyses are conducted. In the second part of the study, an analytical, one-dimensional model is developed integrating the local equations previously defined. The results are expected to be more accurate then the ones obtained in part one, since the fuel cell is considered as a reactor where, for example, hydrogen, carbon monoxide and oxygen react while passing through the cell itself. Consequently, the equations take into account the concentration variation of both the anodic and cathodic gas components along the cell. Moreover, for the anodic gas, the water-shift reaction is also considered.

The environmental benefits related to fuel cells can be enhanced if hydrogen is produced through an environmental friendly practice. Gasification has been widely usied for decades for syngas production from coal, by the so called Integrated Gasification Combined Plants (IGCC), allowing a dramatic emissions reduction, compared to combustion. For these two reasons, several authors have analyzed the possibility of realizing gasification plants coupled with fuel cell systems and, eventually a bottoming cycle. If the gas, however, is produced using a renewable source of energy, such as biomass, the related emissions reduction and fossil fuel preservation represent a further improvement for the environmental performance of the system. In the present study, advantages of an MCFC biogas fueled system is discussed, along with the technical problems related with the integration of the FC section with a Gasifier. Finally, experimental results conducted on a single cell are reported.

Landfill-gas (LFG) is produced as result of the biological reaction of municipal solid waste (MSW). This gas contains about 50% of methane, therefore it cannot be released into the atmosphere as it is because of its greenhouse effect consequences. The high percentage of methane encouraged researchers to find solutions to recover the related energy content for electric energy production. The most common technologies used at the present time are internal combustion reciprocating engines and gas turbines. High conversion efficiency guaranteed by fuel cells (FCs) enable to enhance the energy recovery process and to reduce emissions to air, such as NOx and CO. In any case, in order to investigate the environmental advantages associated with the electric energy generation using fuel cells, it is imperative to consider the whole “life cycle” of the system, “from cradle-to-grave”. In fact, fuel cells are considered to be zero-emission devices, but, for example, emissions associated with their manufacture or for hydrogen production must be considered in order to evaluate all impacts on the environment. In the present work a molten carbonate fuel cell (MCFC) system for LFG recovery is considered and a life cycle assessment (LCA) is conducted for an evaluation of environmental consequences and to provide a guide for further environmental impact reduction.

Fuel cells are considered to be ultra-clean energy conversion systems because the pollutants emitted during their operating time are very low in concentration. For this reason, fuel cells can represent the answer to several environmental issues. What is important, however, is to carefully evaluate if the problem is really being solved, or just shifted. In other words, it is vital to consider not only the operating life, but also the pollution related to the construction, the disposal, the conversion of primary fuel into hydrogen and all the other related operations and systems. The present study is the first step for evaluating the environmental impact related to the whole life cycle of a fuel cell system. In this paper, in fact, the authors, making use of the Life Cycle Assessment (LCA) approach, analyze the impact associated with a Molten Carbonate Fuel Cell Stack. Since the MCFC construction can be considered a novel practice, this study can provide a significant indication for pollution reduction in the stack construction phase.

Achieving energy absorption reductions while improving indoor air quality is a major task when designing new air conditioning systems. A cost-effective way to improve energy efficiency without compromising the thermal comfort consists of developing better control. In the present work, an extensive experimental campaign has been coupled with a theoretical analysis with an effective approach. A simulation tool has been implemented and, through its predictions, an efficient control strategy has been developed in a system that resulted in significant energy savings and environmental benefits. Copyright © 2003 John Wiley & Sons, Ltd.

The necessity of a simulation tool for integrated power plant with MCFCs has led to the development of a numerical model by which it is possible to evaluate the performances of the cell and the plant the cell is embedded in. Many mathematic models can be found in the literature that evaluate electrochemical fuel cell performance [1–9]; however the model must be developed according to a specific target. In other words, if the main purpose of the study is, for example, shape optimization, the model must be very accurate concerning internal conditions, such as current density, temperature distribution, etc. The models found in the literature [1–3, 5, 9] seem to produce excellent results. However, the aim here is to create a mathematical model for fuel cell stacks, which can be integrated into a simulation modular code for the Balance of the Plant (BoP) optimization. Plant modelling can be performed using commercially available software. Often, since fuel cells are innovative devices, numerical codes that simulate their behaviour must be implemented by using a proprietary code. Previous papers can be found in the literature [4, 10, 11], where fuel cell stacks are inserted in an entire power plant, but very often the fuel cell block is zero-dimensional and it is not affected by the variation in input parameters. The authors, for this purpose, have developed a module to be integrated into commercial software for plants simulation, Aspen Plus. The model adopted is simple, but at the same time, it calculates with good accuracy fuel cell performance under any conditions. Another important element taken into account during the code development is the validation through experimental data. In the present work, the authors have adopted an analytic model for evaluating the electrochemical performance [6] of a fuel cell and results obtained are compared with those found out during the tests on a Molten Carbonate Fuel Cell. Some phenomena not described in the original model are considered and an enhanced model for the cell performance is developed. The model obtained is therefore used to analyse fuel cell behaviour under several operating conditions. These results seem to fit very well with experimental analyses conducted in the test rig of the University of Perugia.

The efficient end environmentally friendly production of electricity is undoubtedly one of the 21st century priorities. Since renewable sources will be able to guarantee only a share of the future demand, the present research activity must focus on innovative energy devices and improved conversion systems and cycles. Great expectations are reserved to fuel cell systems. The direct conversion from chemical to electrical energy eliminates environmental problems connected with combustion and bypass the stringent efficiency limit due to Carnot’s principle. Still in infancy, high-temperature fuel cells present the further advantage of feasible cycle integration with steam or gas turbines. In this paper, a molten carbonate fuel cell plant is simulated in a cycle for power generation. The introduction of an external combustion gas turbine is evaluated with the aim of efficiency and net power output increase. The results show that the proposed cycle can be conveniently used as a source of power generation. As compared to internal combustion gas turbine hybrid cycles found in the literature the plant is characterized by fuel cell greater simplicity, due to the absence of pressurization, and gas turbine increased complexity, due to the presence of the heat exchange system.

The constant growth in demand for energy and the awareness of environmental problems requires the development of technologies which lead to significant increases in both energy efficiency and environmental protection. Great expectations have been placed on both simple and hybrid fuel cell plants, thus making necessary the evolution of analysis strategies to evaluate thermodynamic performances, design improvements and acceleration of new developments. This paper investigates the thermodynamic potential of combining a Steam Injected Gas Turbine (STIG) with a Molten Carbonate Fuel Cell (MCFC) for medium and large-scale electrical power production. The MCFC electrochemical core consists of 32 stacks for a total nominal power of 16 MW. The indirect heat transfer to the bottoming cycle allows the GT pressure ratio to be fixed independently from the fuel cell, yielding optimization of the power plant performances in a GT pressure ratios range from 2 to 22. Since the fuel cell exhaust does not have a very high temperature level, the effect of introducing a combustion chamber before the gas turbine is analyzed. The performances of simple and fired bottoming cycles are evaluated and compared as a function of the different parameters in order to identify optimal solutions.

Solid oxide fuel cells (SOFC) are considered a promising technology to be adopted as future possible solution for decentralised combined heat and power (CHP). To operate a SOFC stack in an effective way, the control of some system operation parameters such as anode and cathode feeds, temperature or power output is mandatory. A deep knowledge of transient behaviour is a key requirement to get fuel cell plants ready for an industrial development. In this paper, a 1 kWe SOFC stack is modelled and a possible control strategy is proposed to provide rapid system response to perturbations. The model has been implemented using the commercial software package MATLAB/Simulink. As a result of an external perturbation of steady state conditions, the fuel cell stack control system has to regulate temperature, partial pressure and utilization of flows to avoid degradation of the stack performances.

In the present study, the results of the numerical implementation of a mathematical model of a planar, anode-supported SOFC are reported. The mathematical model is solved in a 3D environment, and is validated by comparison with three different polarization curves, obtained at different operating conditions. The results show the importance of some tridimensional phenomena and their effect on the fuel cell performance. In particular, in-plane diffusion within the electrodes and non-uniform gas distribution within the gas channels are identified and analyzed.

The last two decades have witnessed relevant changes in the economic scenario. After the collapsed of the Eastern block, the East European Countries opened their frontiers to the free market, and encouraged the development of new businesses and new enterprises. At the same time, Nations from Far East, opened new economic policies based on increasing commercial and industrial relations with the most industrialized nations. This world phenomenon is known as globalization. These changes were also promoted by the development of new and more powerful ICT that permit and manage the whole Supply Chain and to successfully support multi sites production strategies. These changes presented a relevant impact also on product design and product life-cycle. Actually now, products are manufactured and used in different continents, with suppliers providing materials from different nations. New models and new instruments have been developed to solve these problems, which are encompassed in the acronym PLM, (Product Life Cycle Management). In this paper, the evolutions of PLM, and its connections with the modern ICT systems will be analyzed and a description will be furnished of a new framework of PLM and its application to an enterprise producing industrial refrigerators mainly in Italy and sold worldwide. This enterprise has to comply with a new regulation (RoHS) that obliged the firm to re-made its own product development process, re-analyze all the components that it uses in production, manage all the data about material composition and organize and develop procedures to collect all the required information. Furthermore, during the project, all these procedures have been implemented on the Enterprise Information System so as to guarantee an efficient informative flow within the firm and among the firm and component suppliers.

Testing the performance of fuel cells is an important key for verifying technology improvements and for demonstrating their potential. However, due to the novelty of this technology, there is not a standardized procedure for testing fuel cell performance. In order to fully investigate fuel cell performance, the behavior must be known under a wide range of operational conditions. Furthermore, in order to compare results coming from different test teams, a set of procedures and parameters to evaluate Single Cell performances should be defined. The research group of the Fuel Cell Laboratory of the University of Perugia is conducting performance tests on single cells, focusing on defining test procedures to find effective parameters to be used to compare tests performed by different teams. This work is about to demonstrate how the testing parameters developed by the team allow one to perform advanced control on test procedures, to understand test results comprehend easily and also to compare them with tests carried out under different operational conditions. The entire analysis is easily conducted by using a single parameter variation hyperspace approach. The experimental results obtained on single fuel cells are reported., JRC.F.2-Cleaner energies

Fuel cells are recognized by all the scientific community to be ultra low emission energy conversion systems, because the pollutants associated with their operation are very low in concentration, compared to traditional energy systems. On the other hand, fuel cells are mainly fed with hydrogen, a chemical component that is not available as a pure component, but it must be extracted from other compounds. This practice involves energy consumption and emissions related to extraction of fuel, hydrogen conversion, transportation and clean up. In order to evaluate the environmental impact related to the energy production by the use of a fuel cell it is imperative to consider all the processes related to the fuel cell operation, and not only the FC operation itself. Life-cycle assessment (LCA) is a unique approach for evaluating the environmental impact related to the whole life of the system, i.e. considering all the processes associated to the system itself, including construction and decommissioning. In the present study a molten carbonate fuel cell (MCFC) system for electric energy production is considered and the related life-cycle environmental impact is considered. Finally a comparison between traditional energy conversion systems and the MCFC systems is conducted, in order to evaluate which are the advantages and the disadvantages that each supposed scenario can lead to.

Wastewater treatment facilities operating with anaerobic digesters produce a methane-rich gas as by-product of the process. In most cases, this gas is released into the atmosphere, thus increasing the greenhouse effect, due to the presence of methane. At the same time, the methane content makes the biogas an interesting source of energy. An efficient energy recovery presents the dual benefits of reducing greenhouse gas emissions and of producing a usable form of energy (typically electric current or heat), using a renewable source of energy, thus diminishing fossil fuel consumption. Due to the high operating temperature, Molten Carbonate Fuel Cells (MCFCs) and Solid Oxide Fuel Cells (SOFCs) present the advantage of being able to operate with a wide variety of fuels, of achieving high energy efficiency and of releasing near-zero emissions. In the present study, the possibility of integrating an anaerobic digester with a high temperature fuel cell is presented. The result of the study illustrates the options, opportunities and the relative benefits and disadvantages related to this energy recovery option.Copyright © 2004 by ASME

The present work aims at evaluating the environmental impact caused by fuel cell systems in the production of electric energy. The very low pollutant emission levels in fuel cells makes them an attractive alternative in ultra clean energy conversion systems. Actually, to truly understand the environmental impact related to fuel cells, it is necessary to study their “cradle-to-grave” life, from the construction phase, during the conversion of primary fuel into hydrogen, to its disposal. The tool used in this analysis is the Life Cycle Assessment approach; in particular the environmental impact of a fuel cell system has been simulated through the software SimaPro 5.0. Thanks to this approach, once the critical process regarding the production of energy by fuel cell system, (i.e. the production of hydrogen by natural gas steam reforming), has been determined, an analysis of the use of landfill gas as a renewable source to produce hydrogen was done. Finally, the production of electric energy by fuel cell systems was compared to that by some conventional energy conversion systems. A second comparison was done between the Molten Carbonate Fuel Cell (MCFC) fuelled by landfill gas and natural gas.Copyright © 2004 by ASME

Fuel Cells are high efficiently chemical energy conversion devices and their promising high performance are recognized by all the scientific community. Their conversion efficiency can be further enhanced recycling the heat content of the exhaust gas for CHP applications or for a bottoming cycle. For this kind of application, high temperature fuel cells (MCFC and SOFC) particularly suit, because outlet gas temperature is relatively high. In previous works (Desideri U. et al. 2001, Lunghi P. and Ubertini S. 2001, Lunghi P., Bove R. and Desideri U. 2002) the possibility of combining an ambient pressure MCFC with a gas turbine has been deeply investigated. Results showed very promising performance only if new designed turbines will be available for an optimised plants combination. The inlet temperature for gas turbine, in fact, is sensible higher than exhaust gas from fuel cell anode and so additional fuel is needed in the bottoming cycle, leading a system efficiency reducing. For this reason, in a previous work (Lunghi P. and Bove R. 2003) it was analyzed the possibility using as bottoming cycle a Steam Turbine Plant equipped with a HRSG for steam generation. In the present work suitable MCFC and Steam Turbine sizes are chosen and a performance analysis is conducting, through numerical simulations. Results showed very high electric efficiency reachable with this plant configuration.Copyright © 2003 by ASME

The increasing need of energy resources along with the growing environmental interest promote the creation of new concepts in the field of energy production and management strategies. The development of high temperature fuel cells, suitable for stationary energy production, is one of the most promising aspects, able to bring a significant change in the power generation scenario. One of the most important features for fuel cells is the potential coupling with advanced gasification systems, thus enabling the possibility of energy recovery from waste, RDF (Refuse Derived Fuel) and biomass. The gasification process transfers the energetic value of the original solid fuel to a gaseous product rich in hydrogen, carbon monoxide and dioxide, and other compounds. A post-gasification treatment removes tars, particulates, impurities and makes the gas suitable for power production in a fuel cell unit. In this work an example of an innovative plant for biomass utilization has been considered. The plant includes a gasification section and a Molten Carbonate Fuel Cell unit, coupled with a hot gas cleanup system. For gasification technology, a recent typology was considered involving an indirect heating system such as the Battelle process. Gaseous streams conveyed to the cell after the conditioning processes were considered. In order to achieve higher efficiencies, a bottoming cycle has been added. It comprises a turbine power plant integrated with the gasification and fuel cell lay-out. In the turbine cycle air is compressed in the operating pressure and internally heated by the waste heat of the fuel cell and of the gasification process. The expanded air is then used in the combustion reactor of the gasification system. The proposed plant allows high electric efficiency and high flexibility in choosing for air compression ratio and unit size; sensitivity analyses were performed.Copyright © 2003 by ASME

Fuel cells are very flexible energy conversion devices and in particular MCFC power generating system are among the most promising for stationary power generation. Potentially, MCFCs can be fed by a great variety of gaseous fuels comprising low calorific values gases like landfill gas. Thanks to fuel processing technologies, like gasification, suitable anode input gases can also be obtained from solid matters. Coal, but also RDF (Refuse Derived Fuel), industrial waste and biomasses are potential fuels for the fuel cell technology after a specific treatment aimed to yield a proper gas for the cell requirements. The gases mentioned above are characterized by low calorific values, presence of inert gases, presence of carbon monoxide and dioxide, presence of various contaminants such as chlorine, sulphur and nitrogen compounds or metals and they can be utilized for power production in high temperature fuel cell units only after a proper clean-up treatment (tars, particulate and sulphur removal). Although interest in alternative fuels for fuel cells has spread in the recent years, most research activity related to fuel treatment has been performed on methane. The biggest drawback deriving from this situation is a general lack of information. When present, moreover, the information is often contradictory. An example of this is given by the acceptable contaminants levels for molten carbonate fuel cells about which there are not values that are based on sufficient experimental evidence. Unfortunately the design of a clean-up system, the choice of the best technology, the optimization of the BOP relies just on these values. In this work a literature research and an analysis of the present knowledge about the effect of impurities in fuel for fuel cells has been preformed. The goal is the definition of concentration levels that can be tolerated by MCFCs and the degradation in performance or the reduction of cell life related to the presence of different pollutants. A second step of the work is the comparison of the levels of impurities tolerated by the cells with those present in the different low calorific value gases in order to define the clean-up requirements. The research priorities in this field have been pointed out. Finally, the project of the fuel cell team of University of Perugia about this topic is briefly described.Copyright © 2003 by ASME

High temperature fuel cells are electricity producers that guarantee relevant energetic and environmental performances. They feature high electricity to input chemical energy ratios and availability of high temperature heat. Notwithstanding, the search for a further increase in electric efficiency, especially when applying a CHP solution is not feasible, has brought to plant integration with gas turbines (GTs) in several studies and some pilot installations. While for pressurized fuel cells the choice of internal combustion gas turbines seem to be the only one feasible, in ambient pressure fuel cells it seems useful to analyze the combination with indirect heated GT. This choice allows to optimize turbine pressure ratio and cell size. In this work, a parametric performance evaluation of a hybrid molten carbonate fuel cell (MCFC) indirect heated gas turbine has been performed by varying the fuel cell section size and the fuel utilization coefficient. The analysis of performance variation with the latter parameter shows how a cell that is optimized for stand alone operation is not necessarily optimized for the integration in a hybrid cycle. Working with reduced utilization factors, in fact can reduce irreversible losses and does not necessarily yield to less electricity production since the heat produced in the post combustor is recovered by the gas turbine section. This aspect has not been taken into sufficient consideration in literature. The analysis illustrates the methodology to define new operating conditions so to allow global output and global efficiency maximization.

Worldwide, the main power source to produce electric energy is represented by fossil fuels, principally used at the present time in large combustion power plants. The main environmental impacts of fossil fuel-fired power plants are the use of non-renewable resources and pollutants emissions. An improvement in electric efficiency would yield a reduction in emissions and resources depletion. In fact, if efficiency is raised, in order to produce an amount unit of electric energy, less fuel is required and consequently less pollutants are released. Moreover, higher efficiency leads to economic savings in operating costs. A generally accepted way of improving efficiency is to combine power plants’ cycles. If one of the combined plants is represented by a fuel cell, both thermodynamic efficiency and emissions level are improved. Fuel cells, in fact, are ultra-clean high efficiency energy conversion devices because no combustion occurs in energy production, but only electrochemical reactions and consequently no NOx and CO are produced inside the cell. Moreover, the final product of the reaction is water that can be released into the atmosphere without particular problems. Second generation fuel cells (Solid Oxide FC and Molten Carbonate FC) are particularly suitable for combining cycles, due to their high operating temperature. In previous works, the authors had analyzed the possibility of combining Molten Carbonate Fuel Cell (MCFC) plant with a Gas Turbine and then a MCFC with a Steam Turbine Plant. Results obtained show that both these configurations allow to obtain high conversion efficiencies and reduced emissions. In the present work, a comparison between MCFC-Gas Turbine and MCFC-Steam Turbine is conducted in order to evaluate the main advantages and disadvantages in adopting one solution instead of the other one.Copyright © 2003 by ASME

Fuel cells have been known theoretically for more than a century. Recently conceived high temperature fuel cells, by guaranteeing higher degrees of efficiencies and greater fuel flexibility, have the potential to yield a radical change in the future of distributed electricity market promising high efficient and ultra-clean power generation. In the last years progress has been so relevant that they seem to be on the verge of commercialization. All plants commissioned seem to consider the parallel flow solution i.e. in which primary fuel flow splits to enter all the stacks that works with nominally equal operational parameters. The present work analysed the possibility of disposing stacks in an array, thus leading to a combination of series and parallel fluid dynamic connection so that one cell anode may have as input the exhaust of another cell anode. The aim is to allow some cells to work with low utilization factors and therefore at greater voltages. Different solutions have been analysed with a tool obtained from the integration of a proprietary code for cells simulation, with Aspen+ flowsheet. Code predictions of cells performances have been validated by experimental campaigns [Lunghi and Burzacca 2002]. The results showed that a noticeable performance increase can be obtained with the proposed configuration without any significant complication in the process. The authors believe that this should be considered as a very interesting research field and strongly encourage participation of the scientific community.Copyright © 2002 by ASME

Fuel cells have resulted to be very attractive power generation systems, promising highly efficient electricity generation with very low environmental impact. Although still in embryonic infancy high-temperature fuel cells, the very high energetic efficiency can be further increased by their integration in hybrid cycles. While a wide variety of potential bottoming technologies for exploiting the high temperature exhaust gases waste heat is available, a lot of research effort is needed to determine the optimal integration of well established technologies with these very novel conversion devices. This work, using results from previous works, in which a MCFC/Gas Turbine hybrid plant was defined and the working parameters optimised both with a GT simple cycle and with steam injection and post combustion, starts from choosing an existing gas turbine technology with suitable working parameters to perform a system evaluation and integration. Since the gas turbine nominal maximum temperature cannot be reached by the only means of heat exchange from the MCFC plant section, post combustion has been considered and the turbine has been simulated both in nominal and in off design conditions in order to find an optimal solution. The work takes into consideration not only the main plants modifications of the existing components to allow for system integration but also the most relevant issues connected with altered working conditions.Copyright © 2002 by ASME

The efficient end environmentally friendly production of electricity is undoubtedly one of the 21st century priorities. Since renewable sources will be able to guarantee only a share of the future demand, the present research activity must focus on innovative energy devices and improved conversion systems and cycles. Great expectations are reserved to fuel cell systems. The direct conversion from chemical to electrical energy eliminates environmental problems connected with combustion and bypass the stringent efficiency limit due to Carnot’s principle. Still in infancy high temperature Fuel cells present the further advantage of feasible cycle integration with steam or gas turbines. In this paper, a Molten Carbonate Fuel Cell plant is simulated in a cycle for power generation. The introduction of an external combustion Gas Turbine is evaluated with the aim of efficiency and net power output increase. The results show that the proposed cycle can be conveniently used as a source of power generation. As compared to internal combustion Gas Turbine hybrid cycles found in literature the plant is characterized by fuel cell greater simplicity, due to the absence of pressurization, and gas turbine increased complexity, due to the presence of the heat exchange system.

Fuel cells have been revealed to be very attractive power generation systems, promising highly efficient electricity generation and very low environmental impact. With the high-temperature fuel cells still in embryonic infancy, the very high energetic efficiency can be further increased by their integration into hybrid cycles. While a wide variety of potential bottoming technologies for the exploitation of the high temperature exhaust gases waste heat is available, a lot of research effort is needed to determine the optimal integration of well established technologies with these very novel conversion devices. The aim of this work is to provide a contribution to selecting promising plants for the electricity generation of the future, and it constitutes an attempt to optimize the working parameters and estimation of the performances. A basic plant configuration and its main working parameters have been determined, including the plant performance, the stream thermodynamic and chemical properties and the component temperatures. A modified plant configuration has been found, allowing the optimal exploitation of the waste heat streams for internal heat regeneration. Different bottoming cycles have been considered, and a parametric analysis has been performed with the aim of performance comparisons. The most promising solution has been determined, and its performance evaluated.

The increasing energy demand along with the growing concern for the environmental issues requires a significant research effort on the development of energy systems with high efficiency and low environmental impact. The use of waste derived fuel in fuel cell systems provides the benefits of high efficiency and very low polluting emissions as well as an effective way of waste disposal. In the present work an investigation of the potential use of waste derived fuel gas in Molten Carbonate fuel cell systems has been performed. A detailed description of the simulation model developed by the authors with the Aspen Plus thermodynamic flow sheet code is presented. The basic configuration of the plant uses pure methane as fuel. An improved plant configuration has been proposed which allows an optimal exploitation of all the thermal streams giving as an output high electrical yield and heat at high temperature. The plant is then adapted to different gas blends as fuel: landfill gas and gas from the gasification of MSW (Municipal Solid Waste). The analysis is focused on the comparison between different fuel gases plants in terms of efficiency, feasibility and process requirements. Depending on the fuel characteristics, different solutions are applied to the plant in order to achieve optimal exploitation of the thermal streams. A general conclusion is that the use of low BTU gas results in an efficient and environmentally sound power generation but leads to a reduction of the plant net power output especially in the case of using gas derived from existing gasification plants. A consistent research activity is required to identify waste derived fuel processing systems that can yield gases which allow an optimal exploitation in fuel cell systems.

The achievement of a more rational use of energy can be difficult when large and complex industrial plants are considered. In the present work, an example is given of how a well-focused energy analysis, based on experimental data, can help to point out possible relevant energy savings. In particular, two different refrigeration systems have been examined for a confectionery plant in different seasons, atmospheric and production conditions, allowing us to understand the actual operation. Based on the analysis of the results, energy saving strategies have been proposed and discussed. Copyright © 2000 John Wiley & Sons, Ltd.

The recent spreading of the interest for fuel cells brings, as a consequence, the need of intense effort for components and system development and testing. While the most resourceful cell developers have realized experimental set-ups for cell duration estimation, it is very rare to find test rigs for complete characterization of cell performance as a function of the numerous input parameters i.e. streams mass flow, composition, temperature and purity, fuel utilization factor, current density. In the present state of the art some modelling of the influence of these factors exists as well as some experimental results for cell potential evaluation at different current densities. What is not found in literature and is difficult to obtain is a complete experimental characterization of fuel cells in which the dependence of performances on a single factor is disaggregated from the others and clearly evaluated. This paper present a test rig for single cell designed to reach these targets and its first tests on a Molten Carbonate Fuel Cell. The experimental setup has revealed to be very flexible allowing the characterization of the system at different operating conditions.

A hydrogen hybrid powertrain has been developed for the Volksbot RT3 differential drive mobile robot in order to obtain a remote-controlled small scale hydrogen car named H2-VOLKS. The powertrain is able to implement any control strategies by setting the instantaneous power split between the fuel cell and the batteries. The robot provides the University of Salento with a low-cost system to test models and develop control strategies applicable to real scale vehicles. In particular, a control strategy presented by the authors in a previous investigation has been optimized with a multi-objective genetic algorithm and tested on the H2-VOLKS.